Surface Modification of Polymers by Blending Siloxane Block Copolymers

The surface modification of a series of homopolymers is accomplished through mixing an AB block copolymer, where B is a poly(dimethylsiloxane) (PDMS) block and A is the block of the same chemical identity as of the homopolymers. The homopolymers are polystyrene, poly (α-methylstyrene), and Bisphenol A polycarbonate. The surface composition of PDMS is measured by angle-dependent electron spectroscopy for chemical analysis (ESCA). The PDMS blocks are segregated in the topmost surface region and constitute up to 90 wt % of the surface of the AB/A blends, even though the overall bulk PDMS concentrations of the blends are 6% or less. The effects of the bulk concentration of the block copolymers, molecular weight, and block copolymer architecture on the surface composition of the AB/A blends are discussed.